Security Settings for Zimbra Collaboration 8.7 series

TBD / WIP

Proxy

DH parameters

Added support for the ssl_dhparam in proxy/nginx. The default DH parameter size is still 1024 bits. With the changes from bug 98852, it is now possible to use a custom (read stronger) key size. However, be aware that some clients may have issues with a size larger than 1024 bits (Java 7 for example, ref: http://httpd.apache.org/docs/trunk/ssl/ssl_faq.html#javadh).